{"id":"https://openalex.org/W7225412841","doi":"https://doi.org/10.3847/1538-4357/aea615","title":"The Relation between Magnetic-field Intensity and Size of the Emission Region in the High-synchrotron-peaked BL Lacertae Object Mrk 421","display_name":"The Relation between Magnetic-field Intensity and Size of the Emission Region in the High-synchrotron-peaked BL Lacertae Object Mrk 421","publication_year":2026,"publication_date":"2026-11-06","ids":{"openalex":"https://openalex.org/W7225412841","doi":"https://doi.org/10.3847/1538-4357/aea615"},"language":"en","primary_location":{"id":"doi:10.3847/1538-4357/aea615","doi":"https://doi.org/10.3847/1538-4357/aea615","is_oa":true,"landing_page_url":"https://doi.org/10.3847/1538-4357/aea615","pdf_url":"https://iopscience.iop.org/article/10.3847/1538-4357/aea615/pdf","source":{"id":"https://openalex.org/S1980519","display_name":"The Astrophysical Journal","issn_l":"0004-637X","issn":["0004-637X","1538-4357"],"is_oa":true,"is_in_doaj":true,"is_core":true,"listed_in":["anvur-scientific","cwts-core","doaj","dongbi-a","jufo-1","ki-jl-1","norway-2","oarl","poland-140","russia-white-list-1","vabb-shw"],"host_organization":"https://openalex.org/P4310320083","host_organization_name":"IOP Publishing","host_organization_lineage":["https://openalex.org/P4310320083","https://openalex.org/P4310311669"],"host_organization_lineage_names":["IOP Publishing","Institute of Physics"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"The Astrophysical Journal","raw_type":"journal-article"},"volume":null,"type":"article","is_traditional":true,"indexed_in":["crossref","doaj"],"open_access":{"is_oa":true,"oa_status":"gold","oa_url":"https://iopscience.iop.org/article/10.3847/1538-4357/aea615/pdf","any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5110646854","display_name":"YunBing XU","orcid":"https://orcid.org/0009-0006-1947-9121","observed_orcids":["https://orcid.org/0009-0006-1947-9121"]},"institutions":[{"id":"https://openalex.org/I120825670","display_name":"Yunnan Normal University","ror":"https://ror.org/00sc9n023","country_code":"CN","type":"education","lineage":["https://openalex.org/I120825670"]},{"id":"https://openalex.org/I189210763","display_name":"Yunnan University","ror":"https://ror.org/0040axw97","country_code":"CN","type":"education","lineage":["https://openalex.org/I189210763"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Y. B. Xu","raw_affiliation_strings":["Yunnan Normal University","Yunnan University"],"raw_orcid":"https://orcid.org/0009-0006-1947-9121","affiliations":[{"raw_affiliation_string":"Yunnan Normal University","institution_ids":["https://openalex.org/I120825670"]},{"raw_affiliation_string":"Yunnan University","institution_ids":["https://openalex.org/I189210763"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5076035489","display_name":"Y. G. Zheng","orcid":"https://orcid.org/0000-0003-0170-9065","observed_orcids":["https://orcid.org/0000-0003-0170-9065"]},"institutions":[{"id":"https://openalex.org/I120825670","display_name":"Yunnan Normal University","ror":"https://ror.org/00sc9n023","country_code":"CN","type":"education","lineage":["https://openalex.org/I120825670"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Y. G. Zheng","raw_affiliation_strings":["Yunnan Normal University"],"raw_orcid":"https://orcid.org/0000-0003-0170-9065","affiliations":[{"raw_affiliation_string":"Yunnan Normal University","institution_ids":["https://openalex.org/I120825670"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5100425605","display_name":"Li Zhang","orcid":"https://orcid.org/0000-0002-5880-8497","observed_orcids":["https://orcid.org/0000-0002-5880-8497"]},"institutions":[{"id":"https://openalex.org/I189210763","display_name":"Yunnan University","ror":"https://ror.org/0040axw97","country_code":"CN","type":"education","lineage":["https://openalex.org/I189210763"]}],"countries":["CN"],"is_corresponding":true,"raw_author_name":"L. Zhang","raw_affiliation_strings":["Yunnan University"],"raw_orcid":"https://orcid.org/0000-0002-5880-8497","affiliations":[{"raw_affiliation_string":"Yunnan University","institution_ids":["https://openalex.org/I189210763"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":2,"corresponding_author_ids":["https://openalex.org/A5100425605"],"corresponding_institution_ids":["https://openalex.org/I189210763"],"apc_list":{"value":4499,"currency":"USD","value_usd":4499},"apc_paid":{"value":4499,"currency":"USD","value_usd":4499},"fwci":0.0,"has_fulltext":true,"cited_by_count":0,"citation_normalized_percentile":{"value":0.0,"is_in_top_1_percent":false,"is_in_top_10_percent":false},"cited_by_percentile_year":null,"biblio":{"volume":"1011","issue":"2","first_page":"271","last_page":"271"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10818","display_name":"Astrophysics and Cosmic Phenomena","score":0.9580000042915344,"subfield":{"id":"https://openalex.org/subfields/3106","display_name":"Nuclear and High Energy Physics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10818","display_name":"Astrophysics and Cosmic Phenomena","score":0.9580000042915344,"subfield":{"id":"https://openalex.org/subfields/3106","display_name":"Nuclear and High Energy Physics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10744","display_name":"Astrophysical Phenomena and Observations","score":0.03700000047683716,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11323","display_name":"Gamma-ray bursts and supernovae","score":0.00139999995008111,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/mrk-421","display_name":"Mrk 421","score":0.996999979019165},{"id":"https://openalex.org/keywords/bl-lac-objects","display_name":"BL Lac objects","score":0.9229999780654907},{"id":"https://openalex.org/keywords/magnetic-field-strength","display_name":"magnetic field strength","score":0.6200000047683716},{"id":"https://openalex.org/keywords/emission-region-size","display_name":"emission region size","score":0.8500000238418579},{"id":"https://openalex.org/keywords/synchrotron-self-compton","display_name":"synchrotron self-Compton","score":0.8669999837875366},{"id":"https://openalex.org/keywords/spectral-energy-distribution","display_name":"spectral energy distribution","score":0.7580000162124634},{"id":"https://openalex.org/keywords/toroidal-magnetic-field","display_name":"toroidal magnetic field","score":0.6470000147819519},{"id":"https://openalex.org/keywords/relativistic-jets","display_name":"relativistic jets","score":0.7749999761581421},{"id":"https://openalex.org/keywords/electron-injection","display_name":"electron injection","score":0.5350000262260437},{"id":"https://openalex.org/keywords/particle-acceleration","display_name":"particle acceleration","score":0.4180000126361847},{"id":"https://openalex.org/keywords/magnetic-reconnection","display_name":"magnetic reconnection","score":0.8169999718666077},{"id":"https://openalex.org/keywords/poynting-flux","display_name":"Poynting flux","score":0.781000018119812},{"id":"https://openalex.org/keywords/jet-power","display_name":"jet power","score":0.49900001287460327},{"id":"https://openalex.org/keywords/activity-states","display_name":"activity states","score":0.42899999022483826}],"concepts":[{"id":"https://openalex.org/C121332964","wikidata":"https://www.wikidata.org/wiki/Q413","display_name":"Physics","level":0,"score":0.9746000170707703},{"id":"https://openalex.org/C111717503","wikidata":"https://www.wikidata.org/wiki/Q195385","display_name":"BL Lac object","level":4,"score":0.7821000218391418},{"id":"https://openalex.org/C44870925","wikidata":"https://www.wikidata.org/wiki/Q37547","display_name":"Astrophysics","level":1,"score":0.7138000130653381},{"id":"https://openalex.org/C74902906","wikidata":"https://www.wikidata.org/wiki/Q1190858","display_name":"Radiative transfer","level":2,"score":0.6037999987602234},{"id":"https://openalex.org/C119947313","wikidata":"https://www.wikidata.org/wiki/Q5596635","display_name":"Jet (fluid)","level":2,"score":0.590399980545044},{"id":"https://openalex.org/C93038891","wikidata":"https://www.wikidata.org/wiki/Q1061524","display_name":"Intensity (physics)","level":2,"score":0.5181000232696533},{"id":"https://openalex.org/C115260700","wikidata":"https://www.wikidata.org/wiki/Q11408","display_name":"Magnetic field","level":2,"score":0.4742000102996826},{"id":"https://openalex.org/C99844830","wikidata":"https://www.wikidata.org/wiki/Q102441924","display_name":"Scaling","level":2,"score":0.4449999928474426},{"id":"https://openalex.org/C15001198","wikidata":"https://www.wikidata.org/wiki/Q3241394","display_name":"Toroid","level":3,"score":0.4277999997138977},{"id":"https://openalex.org/C147120987","wikidata":"https://www.wikidata.org/wiki/Q2225","display_name":"Electron","level":2,"score":0.42399999499320984},{"id":"https://openalex.org/C153385146","wikidata":"https://www.wikidata.org/wiki/Q18335","display_name":"Radiation","level":2,"score":0.3853999972343445},{"id":"https://openalex.org/C19499675","wikidata":"https://www.wikidata.org/wiki/Q232207","display_name":"Monte Carlo method","level":2,"score":0.3804999887943268},{"id":"https://openalex.org/C30475298","wikidata":"https://www.wikidata.org/wiki/Q909554","display_name":"Computational physics","level":1,"score":0.37070000171661377},{"id":"https://openalex.org/C111350023","wikidata":"https://www.wikidata.org/wiki/Q1191869","display_name":"Markov chain Monte Carlo","level":3,"score":0.33410000801086426},{"id":"https://openalex.org/C163752227","wikidata":"https://www.wikidata.org/wiki/Q1253365","display_name":"Radiant intensity","level":3,"score":0.31630000472068787},{"id":"https://openalex.org/C162565982","wikidata":"https://www.wikidata.org/wiki/Q3725254","display_name":"Magnetic energy","level":4,"score":0.2750000059604645},{"id":"https://openalex.org/C168110828","wikidata":"https://www.wikidata.org/wiki/Q1331626","display_name":"Spectral density","level":2,"score":0.27129998803138733},{"id":"https://openalex.org/C36819163","wikidata":"https://www.wikidata.org/wiki/Q287506","display_name":"Magnetic reconnection","level":3,"score":0.2678999900817871},{"id":"https://openalex.org/C4839761","wikidata":"https://www.wikidata.org/wiki/Q212111","display_name":"Spectral line","level":2,"score":0.2624000012874603},{"id":"https://openalex.org/C12287442","wikidata":"https://www.wikidata.org/wiki/Q105902","display_name":"Luminosity","level":3,"score":0.25600001215934753},{"id":"https://openalex.org/C98763669","wikidata":"https://www.wikidata.org/wiki/Q176645","display_name":"Markov chain","level":2,"score":0.2531000077724457}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.3847/1538-4357/aea615","doi":"https://doi.org/10.3847/1538-4357/aea615","is_oa":true,"landing_page_url":"https://doi.org/10.3847/1538-4357/aea615","pdf_url":"https://iopscience.iop.org/article/10.3847/1538-4357/aea615/pdf","source":{"id":"https://openalex.org/S1980519","display_name":"The Astrophysical Journal","issn_l":"0004-637X","issn":["0004-637X","1538-4357"],"is_oa":true,"is_in_doaj":true,"is_core":true,"listed_in":["anvur-scientific","cwts-core","doaj","dongbi-a","jufo-1","ki-jl-1","norway-2","oarl","poland-140","russia-white-list-1","vabb-shw"],"host_organization":"https://openalex.org/P4310320083","host_organization_name":"IOP Publishing","host_organization_lineage":["https://openalex.org/P4310320083","https://openalex.org/P4310311669"],"host_organization_lineage_names":["IOP Publishing","Institute of Physics"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"The Astrophysical Journal","raw_type":"journal-article"},{"id":"pmh:oai:doaj.org/article:613a819a083d408da36293cf990ce864","doi":null,"is_oa":false,"landing_page_url":"https://doaj.org/article/613a819a083d408da36293cf990ce864","pdf_url":null,"source":{"id":"https://openalex.org/S4306401280","display_name":"DOAJ (DOAJ: Directory of Open Access Journals)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"The Astrophysical Journal, Vol 1011, Iss 2, p 271 (2026)","raw_type":"article"}],"best_oa_location":{"id":"doi:10.3847/1538-4357/aea615","doi":"https://doi.org/10.3847/1538-4357/aea615","is_oa":true,"landing_page_url":"https://doi.org/10.3847/1538-4357/aea615","pdf_url":"https://iopscience.iop.org/article/10.3847/1538-4357/aea615/pdf","source":{"id":"https://openalex.org/S1980519","display_name":"The Astrophysical Journal","issn_l":"0004-637X","issn":["0004-637X","1538-4357"],"is_oa":true,"is_in_doaj":true,"is_core":true,"listed_in":["anvur-scientific","cwts-core","doaj","dongbi-a","jufo-1","ki-jl-1","norway-2","oarl","poland-140","russia-white-list-1","vabb-shw"],"host_organization":"https://openalex.org/P4310320083","host_organization_name":"IOP Publishing","host_organization_lineage":["https://openalex.org/P4310320083","https://openalex.org/P4310311669"],"host_organization_lineage_names":["IOP Publishing","Institute of Physics"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"The Astrophysical Journal","raw_type":"journal-article"},"sustainable_development_goals":[],"study_designs":[],"awards":[{"id":"https://openalex.org/G1283919031","display_name":null,"funder_award_id":"12233006","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"}],"funders":[{"id":"https://openalex.org/F4320321001","display_name":"National Natural Science Foundation of China","ror":"https://ror.org/01h0zpd94"}],"has_content":{"grobid_xml":true,"pdf":true},"content_urls":{"pdf":"https://content.openalex.org/works/W7225412841.pdf","grobid_xml":"https://content.openalex.org/works/W7225412841.grobid-xml"},"referenced_works_count":127,"referenced_works":["https://openalex.org/W37960100","https://openalex.org/W1923251529","https://openalex.org/W1951204806","https://openalex.org/W1953516118","https://openalex.org/W1968898498","https://openalex.org/W1970672826","https://openalex.org/W1972799310","https://openalex.org/W1976354101","https://openalex.org/W1976561494","https://openalex.org/W1979115990","https://openalex.org/W1980799261","https://openalex.org/W1983354252","https://openalex.org/W1983650180","https://openalex.org/W1983791096","https://openalex.org/W1986484971","https://openalex.org/W1993216065","https://openalex.org/W1995610395","https://openalex.org/W2002690879","https://openalex.org/W2004048353","https://openalex.org/W2005117828","https://openalex.org/W2009953698","https://openalex.org/W2012372085","https://openalex.org/W2023347320","https://openalex.org/W2024214727","https://openalex.org/W2028998331","https://openalex.org/W2029599444","https://openalex.org/W2030100334","https://openalex.org/W2033258958","https://openalex.org/W2036385708","https://openalex.org/W2037083259","https://openalex.org/W2037970068","https://openalex.org/W2038367995","https://openalex.org/W2039582625","https://openalex.org/W2040317164","https://openalex.org/W2044525249","https://openalex.org/W2047454714","https://openalex.org/W2047566252","https://openalex.org/W2048364703","https://openalex.org/W2049177115","https://openalex.org/W2056313509","https://openalex.org/W2056529704","https://openalex.org/W2056577833","https://openalex.org/W2056713841","https://openalex.org/W2057862339","https://openalex.org/W2063397409","https://openalex.org/W2068860926","https://openalex.org/W2071065321","https://openalex.org/W2079525399","https://openalex.org/W2084342493","https://openalex.org/W2088868638","https://openalex.org/W2090180962","https://openalex.org/W2091663789","https://openalex.org/W2092595637","https://openalex.org/W2097227216","https://openalex.org/W2098597426","https://openalex.org/W2101010519","https://openalex.org/W2105917601","https://openalex.org/W2110164985","https://openalex.org/W2110320627","https://openalex.org/W2113503986","https://openalex.org/W2114880118","https://openalex.org/W2115060210","https://openalex.org/W2119837857","https://openalex.org/W2120289895","https://openalex.org/W2122332384","https://openalex.org/W2130030500","https://openalex.org/W2135101687","https://openalex.org/W2140435052","https://openalex.org/W2141389126","https://openalex.org/W2145566627","https://openalex.org/W2147412917","https://openalex.org/W2149990597","https://openalex.org/W2152242740","https://openalex.org/W2153550023","https://openalex.org/W2154215992","https://openalex.org/W2155351844","https://openalex.org/W2155689241","https://openalex.org/W2156720412","https://openalex.org/W2169080969","https://openalex.org/W2170660629","https://openalex.org/W2175126857","https://openalex.org/W2191829672","https://openalex.org/W2198375046","https://openalex.org/W2202345436","https://openalex.org/W2207575441","https://openalex.org/W2293040502","https://openalex.org/W2303796752","https://openalex.org/W2419525773","https://openalex.org/W2547766602","https://openalex.org/W2560859645","https://openalex.org/W2610478920","https://openalex.org/W2736499461","https://openalex.org/W2751774114","https://openalex.org/W2768914878","https://openalex.org/W2792882148","https://openalex.org/W2794388434","https://openalex.org/W2807078946","https://openalex.org/W2811921651","https://openalex.org/W2921812053","https://openalex.org/W2943468458","https://openalex.org/W2949917926","https://openalex.org/W2963228599","https://openalex.org/W2969756228","https://openalex.org/W2972425017","https://openalex.org/W3009646154","https://openalex.org/W3010748784","https://openalex.org/W3011224385","https://openalex.org/W3022002556","https://openalex.org/W3033454972","https://openalex.org/W3043466863","https://openalex.org/W3102059128","https://openalex.org/W3106889297","https://openalex.org/W3118303909","https://openalex.org/W3156272039","https://openalex.org/W4200021955","https://openalex.org/W4206230465","https://openalex.org/W4301183217","https://openalex.org/W4309754538","https://openalex.org/W4384561389","https://openalex.org/W4386441156","https://openalex.org/W4388266624","https://openalex.org/W4392293429","https://openalex.org/W4392382294","https://openalex.org/W4394642639","https://openalex.org/W4398213978","https://openalex.org/W4398781600","https://openalex.org/W7095494839"],"related_works":["https://openalex.org/W7056323840","https://openalex.org/W1972799310","https://openalex.org/W2774895949","https://openalex.org/W4298120738","https://openalex.org/W3200955134","https://openalex.org/W2964239529","https://openalex.org/W3130813307","https://openalex.org/W3011224385","https://openalex.org/W2002690879","https://openalex.org/W2083672682"],"abstract_inverted_index":{"Abstract":[0],"Magnetic":[1],"effects":[2],"are":[3],"thought":[4],"to":[5,40,118,134],"dominate":[6],"the":[7,15,24,48,66,78,135,168,185,192],"formation":[8],"of":[9,19,47,80,161],"BL":[10,50],"Lac":[11,51],"object":[12,52],"jets,":[13],"but":[14],"role":[16],"and":[17,72,76,87,184],"influence":[18],"large-scale":[20],"magnetic":[21,85,128,177],"fields":[22],"within":[23],"jets":[25],"remains":[26],"incompletely":[27],"understood.":[28],"We":[29,64,91],"utilize":[30],"a":[31,93,126],"one-zone":[32],"synchrotron-self-Compton":[33],"(SSC)":[34],"model":[35,137],"with":[36,122],"broken-power-law":[37],"electron":[38],"injection":[39],"reproduce":[41],"multiwavelength":[42],"spectral":[43],"energy":[44],"distributions":[45],"(SEDs)":[46],"high-synchrotron-peaked":[49],"Mrk":[53],"421":[54],"for":[55,125,191],"73":[56],"activity":[57,182],"states,":[58,183],"constraining":[59],"six":[60],"key":[61],"physical":[62],"parameters.":[63],"investigate":[65],"correlation":[67],"between":[68],"magnetic-field":[69],"strength":[70],"B":[71,97,152],"emission-region":[73,166],"size":[74],"R":[75,106,154],"estimate":[77],"powers":[79],"relativistic":[81],"electrons,":[82],"cold":[83],"protons,":[84],"fields,":[86],"total":[88],"jet":[89,169],"power.":[90,195],"find":[92],"significant":[94],"anticorrelation":[95],"log":[96,105],"=":[98],"(":[99,108],"\u2212":[100],"0.93":[101],"\u00b1":[102,110],"0.05":[103],")":[104,112],"+":[107],"14.22":[109],"0.83":[111],".":[113],"The":[114],"derived":[115],"slope":[116],"close":[117],"\u22121":[119],"is":[120,156,170],"compatible":[121],"theoretical":[123],"expectations":[124],"toroidal":[127],"geometry,":[129],"though":[130],"parameter":[131,163],"couplings":[132],"inherent":[133],"leptonic":[136],"cannot":[138,189],"be":[139],"fully":[140],"excluded.":[141],"Markov":[142],"Chain":[143],"Monte":[144],"Carlo":[145],"(MCMC)":[146],"posterior":[147],"analyses":[148],"demonstrate":[149],"that":[150],"this":[151],"\u2013":[153],"scaling":[155],"not":[157],"merely":[158],"an":[159],"artefact":[160],"intra-epoch":[162],"degeneracy.":[164],"On":[165],"scales":[167],"particle-kinetic-energy":[171],"dominated;":[172],"distinct":[173],"electron-acceleration":[174],"mechanisms":[175],"(shocks,":[176],"reconnection)":[178],"operate":[179],"across":[180],"different":[181],"conventional":[186],"Poynting-flux-dominated":[187],"scenario":[188],"account":[190],"observed":[193],"radiative":[194]},"counts_by_year":[],"updated_date":"2026-11-10T11:39:43.021295","created_date":"2026-11-07T00:00:00"}
